How does vertical reading affect reading speed?

Purpose: Vertical reading is an adaptive reading strategy sometimes used in homonymous hemianopia. This study aimed to measure horizontal and vertical reading speeds in visually normal volunteers using the Radner Reading Chart. Methods: Fifteen orthoptic students, mean age 19.7 years, took part in this repeated measures study. Participants read sentences aloud from the Radner Reading Chart horizontally and rotated vertically, to read up and down the line. Words read correctly and the time taken to read each sentence were recorded. Results: Reading speeds were calculated (words read correctly per second) for horizontal text (2.95 words per second) and for vertical text, reading up the line (1.73 words per second) and reading down the line (1.57 words per second). Reading horizontal text was significantly faster than reading vertical text. Reading horizontal text was 1.22 words per second faster than reading text vertically up (p < 0.0001) and 1.38 words per second faster than text vertically down (p < 0.0001). There was no statistically significant difference between reading text vertically up the line and vertically down the line (0.16 words per second, p = 0.42). Conclusion: Horizontal reading speed, measured with the Radner Reading Chart, was significantly faster than both vertical reading speeds. There was no significant difference between reading vertically up the line and reading vertically down the line. The slower time taken to read the vertically orientated sentences had a greater effect on reading speed than the number of errors made

Surgery to Treat Residual Acquired Excyclotropia without Changing the Primary Position Vertical Deviation: A Case Report

Aim: To describe the surgical management and long-term outcome of a case of symptomatic residual acquired primary position excyclotropia, without changing the primary position vertical deviation. Methods: This case report describes ipsilateral half tendon width transpositions of the left superior rectus temporally and inferior rectus nasally, combined with right inferior rectus posterior fixation suture at 11 mm. Results: Three days postoperatively, the transposition procedure produced a 10° cyclotorsional change in primary position, resulting in 5° of incyclotorsion (double Maddox rod). Six weeks postoperatively, the incyclotorsion regressed to 1° (synoptophore) and a central field of binocular single vision (BSV) (90° horizontally and 60° vertically) was demonstrated without an abnormal head posture. Fifteen months postoperatively, 1° primary position incyclotorsion (Torsionometer) and the central field of BSV remained stable. The primary position vertical deviation was changed by 1 prism diopter and no V pattern was induced. Conclusion: In our case, ipsilateral half tendon width horizontal transpositions of the vertical recti achieved satisfactory correction of excyclotorsion and restored BSV without significantly changing the primary position vertical deviation. The result was stable 15 months postoperatively

A case report of progressive Brown syndrome?

Aim: To report an unusual case of progressive Brown syndrome and the successful surgical treatment. Methods: A 42-year-old male with a documented 14-year history of progressive Brown syndrome is presented. To improve diplopia symptoms an ipsilateral superior oblique (SO) 7 mm silicone tendon spacer and a contralateral 3 mm superior rectus (SR) recession were performed. Results: The surgical procedure was successful in reducing the primary position deviation (preoperative 30ΔLHoT 7ΔLXT; one month post surgery 3ΔLHo; one year post surgery 7-8ΔLHo 1-2ΔE) and eliminating the abnormal head posture (AHP). Diplopia was only reported on elevation and depression following surgery. Conclusion: This case of Brown syndrome is unusual as it was progressive and had a documented history over a number of years prior to surgery. Surgical treatment of Brown syndrome is rarely required, but in this case was successful in improving the patient’s diplopia and AHP

The provision of patient information about nystagmus

Aims: The aims of this study were to evaluate the current provision of patient information about nystagmus in orthoptic clinics in the UK and Ireland and to develop a standardised information pack about nystagmus. Methods: A questionnaire was circulated to orthoptists in the UK and Ireland asking whether they had information to provide to patients with nystagmus, what was included in this information and how it could be improved. Orthoptists were also asked what should be included in a standardised information pack about nystagmus. Results: Two hundred and thirty three orthoptists completed the questionnaire. One-third of responding orthoptists did not have information to provide to patients with nystagmus. Most reported the information available to them included details of support services and physical symptoms. Including information about living with nystagmus at different ages and long-term prognosis were the most common suggestions to improve information about nystagmus. More than half of orthoptists selected all the suggested topics to be included in a standardised information pack, with support services and long-term prognosis most frequently selected. Conclusions: Only 67% of responding orthoptists had information about nystagmus to give to patients or their families. Ways to improve the current information and content considered important by orthoptists were taken into account to create a nystagmus information pack, which is now available online

Simulation of oscillopsia in virtual reality

Purpose: Nystagmus is characterised by involuntary eye movement. A proportion of those with nystagmus experience the world constantly in motion as their eyes move: a symptom known as oscillopsia. Individuals with oscillopsia can be incapacitated and often feel neglected due to limited treatment options. Effective communication of the condition is challenging and no tools to aid communication exist. This paper describes a virtual reality (VR) application that recreates the effects of oscillopsia, enabling others to appreciate the condition. Methods: Eye tracking data was incorporated into a VR oscillopsia simulator and released as a smartphone app – “Nystagmus Oscillopsia Sim VR”. When a smartphone is used in conjunction with a Google Cardboard headset, it presents an erratic image consistent with oscillopsia. The oscillopsia simulation was appraised by six participants for its representativeness. These individuals have nystagmus and had previously experienced oscillopsia but were not currently symptomatic; they were therefore uniquely placed to judge the app. The participants filled in a questionnaire to record impressions and the usefulness of the app. Results: The published app has been downloaded ~3700 times (28/02/2018) and received positive feedback from the nystagmus community. The validation study questionnaire scored the accuracy of the simulation an average of 7.8/10 while its ability to aid communication received 9.2/10. Conclusion: The evidence indicates that the simulation can effectively recreate the sensation of oscillopsia and facilitate effective communication of the symptoms associated with the condition. This has implications for communication of other visual conditions

A joint role for forced and internally-driven variability in the decadal modulation of global warming

Despite the observed monotonic increase in greenhouse-gas concentrations, global mean temperature displays important decadal fluctuations typically attributed to both external forcing and internal variability. Here, we provide a robust quantification of the relative contributions of anthropogenic, natural, and internally-driven decadal variability of global mean sea surface temperature (GMSST) by using a unique dataset consisting of 30-member large initial-condition ensembles with five Earth System Models (ESM-LE). We present evidence that a large fraction (~29–53%) of the simulated decadal-scale variance in individual timeseries of GMSST over 1950–2010 is externally forced and largely linked to the representation of volcanic aerosols. Comparison with the future (2010–2070) period suggests that external forcing provides a source of additional decadal-scale variability in the historical period. Given the unpredictable nature of future volcanic aerosol forcing, it is suggested that a large portion of decadal GMSST variability might not be predictable

Revisiting ENSO and IOD Contributions to Australian Precipitation

Tropical modes of variability, such as El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD), exert a strong influence on the interannual variability of Australian precipitation. Nevertheless, commonly used indices of ENSO and IOD variability display significant co-variability that prevents a robust quantification of the independent contribution of each mode to precipitation anomalies. This co-variability issue is often addressed by statistically removing ENSO or IOD variability from the precipitation field before calculating teleconnection patterns. However, by performing a suite of coupled and uncoupled modeling experiments in which either ENSO or IOD variability is physically removed, we show that ENSO-only-driven precipitation patterns computed by statistically removing the IOD influence significantly underestimate the impact of ENSO on Australian precipitation variability. Inspired by this, we propose a conceptual model that allows one to effectively separate the contribution of each mode to Australian precipitation variability

The assessment of vision in children with severe learning difficulties: a systematic review

Background Children with learning difficulties that require a vision assessment may not be able to perform standard clinical vision tests, for example, Forced Choice Preferential Looking (FCPL). There is a lack of standardisation on the procedure of vision assessment in this group of children. The aim of this literature review was to identify and evaluate methods of vision assessment when standard clinical vision tests are not possible in children with severe learning difficulties. Method Three databases (CINAHL, PubMed, Web of Science) were searched from inception to Nov 2022 for methods of vision assessment in children with learning difficulties. Reference lists and grey literature were also searched. The McMaster University Critical review form for quantitative studies was used to assess the methodological quality of the primary studies identified. Results Five-hundred and seventy one papers were identified from databases and 16 were identified from searching reference lists and grey literature. Of the 587, five studies were relevant and fulfilled all the inclusion and exclusion criteria. Three methods of vision assessment were identified: Visually Evoked Potentials (VEP), questionnaires, and the Bradford visual function box (BVFB). Discussion The VEP method was validated and reliable, although it had a similar success rate to the standardised FCPL tests in children with learning difficulties. The BVFB was a standardised method for measurement of vision threshold in children that cannot successfully complete FCPL tests, however it has not been validated. Questionnaires are an efficient way to gather descriptive information on the child's functional vision, however no guidance on the interpretation of the information is available. The BVFB and questionnaires require further development and validation. All three methods (VEP, questionnaires, and BVFB) can be useful as part of the assessment of vision in a child with severe learning difficulties where standard clinical tests are not possible, when used in a standardised manner

The Impact of Diplopia on Reading

Aim: To compare the effect of induced vertical diplopia (small and large separation) on reading speed and accuracy. Method: The Radner Reading Chart (RRC) was used to measure reading speed (correct words per minute (wpm)) and accuracy (percentage). Accuracy was measured using two different methods: ‘accuracy-omission’ where only the omission of a word reduced the score, and ‘accuracy-addition and omission’ where any error reduced the score. Three viewing conditions were created using Fresnel prisms on plano glasses: a control condition without diplopia (6 prism dioptres (Δ) base up (BU) over each eye), small separation vertical diplopia (3Δ BU right eye and 3Δ base down (BD) left eye) and large separation vertical diplopia (6Δ BU right eye and 6Δ BD left eye). Viewing conditions were counterbalanced to minimise order effects. Results: Twenty-four participants were included with a mean age of 20.1 years. The mean reading speed in the control condition was 156.90 wpm. Both diplopic conditions significantly reduced the reading speed compared to the control condition, small separation diplopia to 62.75 wpm (p < 0.001) and large separation diplopia to 105.71 wpm (p < 0.001). The mean reading speed with small separation diplopia was significantly slower than the mean reading speed with large separation diplopia (p < 0.01). Median accuracy scores in the control and the large separation diplopia conditions were 100% using both methods of measuring accuracy. The small separation diplopia condition significantly reduced accuracy to 92.86% (accuracy-omission method) and to 57.50% (accuracy-addition and omission method) compared to the control condition (p < 0.01) and the large separation diplopia condition (p < 0.05). Conclusion: When vertical diplopia was induced using Fresnel prisms, diplopia of smaller separation resulted in the greatest reduction in reading speed and accuracy, compared to without diplopia and large separation diplopia